As will be appreciated herein below, except as otherwise indicated, alloy designations and temper designations refer to the Aluminum Association designations in Aluminum Standards and Data and the Registration Records, as published by the Aluminum Association in 2006.
For any description of alloy compositions or preferred alloy compositions, all references to percentages are by weight percent unless otherwise indicated.
Designers and manufacturers in particular in the aerospace industry are constantly trying to improve fuel efficiency, product performance and constantly trying to reduce manufacturing, maintenance and service costs. One way of achieving these goals is by improving the relevant properties of the used aluminium alloys so that a structure made from a particular alloy can be designed more effectively or will have a better overall performance. By improving the relevant material properties for a particular application, also the service costs can be significantly reduced by longer inspection intervals of the structure such as an aeroplane.
The main application of AA2000 series aluminium alloys in aeroplanes is as fuselage or skin plate, for which purpose typically AA2024 and AA2524 in the T351 temper are used or as lower wing plate for which purpose typically AA2024 in the T351 temper and AA2324 in the T39 temper is used. For these applications high tensile strength and high toughness are required. It is known that these properties of an AA2000 series aluminium alloy can be improved by higher levels of alloying elements such as Cu, Mg and Ag. In these types of alloy products the levels of Fe and Si are being kept at a levels as low as practical, for both elements typically each <0.1 and more preferably <0.07, in order to maintain the desired level of damage tolerance properties.
The most commonly used aluminium alloys form the AA2000-type series for aerospace application are AA2024, AA2024HDT (“High Damage Tolerant”) and AA2324.
For newly designed aeroplanes, there is a wish for even better properties of the aluminium alloys than the known alloys have in order to design aeroplanes which are more manufacturing and operationally cost effective. Accordingly, a need exists for an aluminium alloy capable of achieving an improved balance of properties of the aluminium alloy in the relevant form.